U.S. patent number 10,231,822 [Application Number 15/593,715] was granted by the patent office on 2019-03-19 for thoracic aorta stent graft.
This patent grant is currently assigned to Cook Medical Technologies LLC. The grantee listed for this patent is Cook Medical Technologies LLC. Invention is credited to David Ernest Hartley.
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United States Patent |
10,231,822 |
Hartley |
March 19, 2019 |
**Please see images for:
( Certificate of Correction ) ** |
Thoracic aorta stent graft
Abstract
A stent graft for placement in the thoracic arch of a patient
has a tubular body defining a main lumen therethrough, a plurality
of zig zag stents along the tubular body, each of the stents
comprising a plurality of struts and bends, the bends being between
adjacent struts. At least a first stent and an adjacent second
stent having at least a pair of adjacent bends on the first stent
aligned with an adjacent pair of bends on the second stent, whereby
a first pair of adjacent struts of the first stent and a second
pair of adjacent struts of the second adjacent stent together
define a diamond shape region. A recess is within the diamond
shaped region with the recess extending into the lumen of the
tubular body. A fenestration extending into the tubular body within
the recess in the diamond shaped region and a graft tube leading
from the fenestration into the main lumen. There can be one, two or
three diamond shaped regions, recesses, fenestrations and graft
tubes. Proximally of the or each diamond shaped region the tubular
body has a first diameter, distally of the diamond shaped region
the tubular body has a second diameter and in the region of the
tubular body around the diamond shaped region the tubular body has
a third diameter, the first diameter being greater than the second
diameter and both the first and second diameter being greater than
the third diameter whereby a central region is defined which will
allow circumferential blood flow during an operation out of the
graft tube into the recess and then into the central region.
Inventors: |
Hartley; David Ernest
(Wannanup, AU) |
Applicant: |
Name |
City |
State |
Country |
Type |
Cook Medical Technologies LLC |
Bloomington |
IN |
US |
|
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Assignee: |
Cook Medical Technologies LLC
(Bloomington, IN)
|
Family
ID: |
43778462 |
Appl.
No.: |
15/593,715 |
Filed: |
May 12, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170245978 A1 |
Aug 31, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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13576348 |
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9649188 |
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PCT/US2011/024148 |
Feb 9, 2011 |
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61302586 |
Feb 9, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F
2/915 (20130101); A61F 2/07 (20130101); A61F
2002/061 (20130101); A61F 2/954 (20130101); A61F
2002/826 (20130101); A61F 2250/0039 (20130101); A61F
2002/075 (20130101); A61F 2/856 (20130101); A61F
2210/0014 (20130101); A61F 2/89 (20130101) |
Current International
Class: |
A61F
2/07 (20130101); A61F 2/915 (20130101); A61F
2/82 (20130101); A61F 2/06 (20130101); A61F
2/89 (20130101); A61F 2/954 (20130101); A61F
2/856 (20130101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2010202544 |
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Aug 2010 |
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AU |
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2005-521471 |
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Jul 2005 |
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JP |
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2012-501208 |
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Jan 2012 |
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JP |
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WO 2003/082153 |
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Oct 2003 |
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WO |
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WO 2008/021557 |
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Feb 2008 |
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WO |
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WO 2010/024879 |
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Mar 2010 |
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WO |
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WO 2011/159324 |
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Dec 2011 |
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WO |
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Other References
Examination report for corresponding EP Application No.
11703804.2-1651, dated Apr. 2, 2015, 6 pgs. cited by applicant
.
First Examination Report for Australian Patent Application No.
2011215968 dated Jan. 24, 2013, 2 pgs. cited by applicant .
Japanese Office Action/Notification for Reason for Rejection for
corresponding JP 2012-552939, dated Dec. 2, 2014, 4 pgs. cited by
applicant .
Japanese Office Action and English translation for JP Patent
Application No. 2012-552939, dated Sep. 8, 2015, 4 pgs. cited by
applicant .
Notification of Transmittal of the International Search Report and
the Written Opinion of the International Searching Authority,
International Application No. PCT/US2011/024148, dated Apr. 12,
2011, p. 1-13. cited by applicant .
International Preliminary Report on Patentability for
PCT/US2011/024148, dated Aug. 14, 2012, 8 pgs. cited by applicant
.
Canadian Office Action for CA Application No. 2,788,838, dated Jun.
29, 2016, 2 pgs. cited by applicant.
|
Primary Examiner: Sharma; Yashita
Assistant Examiner: Preston; Rebecca
Attorney, Agent or Firm: Brinks Gilson & Lione
Parent Case Text
RELATED APPLICATIONS
This application is a continuation of U.S. Ser. No. 13/576,348,
filed Jul. 31, 2012, which is a National Stage of International
Application No. PCT/US2011/024148, filed Feb. 9, 2011, which claims
the benefit of the filing date under 35 U.S.C. .sctn. 119(e) of
Provisional U.S. Patent Application Ser. No. 61/302,586, filed Feb.
9, 2010. All of the foregoing applications are hereby incorporated
by reference in their entirety.
Claims
The invention claimed is:
1. A stent graft for placement in a vessel of a patient, the stent
graft comprising: a tubular body of graft material, the tubular
body having a proximal inflow end, a distal outflow end, a main
lumen therethrough, and a sidewall from the proximal inflow end to
the distal outflow end; a plurality of stents along the tubular
body, including a first stent and second stent adjacent the first
stent; a first recessed region in the graft material, the first
recessed region defined by a recessed portion of the graft material
of the tubular body that extends into the main lumen of the tubular
body and a second recessed region defined by a second recessed
portion of the graft material of the tubular body that extends into
the main lumen of the tubular body, wherein the first recessed
region and the second recessed region share a boundary; a first
fenestration in the first recessed region of the graft material, a
second fenestration in the second recessed region of the graft
material, each of the first and second fenestrations opening into
the tubular body, wherein the first and second fenestrations are
both circumferentially and longitudinally offset from each
other.
2. The stent graft of claim 1, further comprising: a first graft
tube leading from the first fenestration into the main lumen toward
the proximal inflow end and a second graft tube leading from the
second fenestration into the main lumen toward the proximal inflow
end.
3. The stent graft of claim 2, where in the first graft tube has a
first diameter and the second graft has a second diameter greater
than the first diameter.
4. The stent graft of claim 2, wherein the first and second graft
tubes each comprise a space frame having first and second circular
ring portions spaced apart axially and at least two struts
extending between the first and second circular ring portions.
5. The stent graft of claim 2, wherein the first and second graft
tubes each comprise a cylindrical portion, each cylindrical portion
comprises an assembly of two individual ring and strut components,
each ring and strut component comprising a circular ring portion
defining a plane of the circular ring portion and a strut extending
at right angles to the plane of the circular ring portion from a
periphery of the circular ring portion.
6. The stent graft of claim 1, wherein each of the first and second
recessed regions have a proximal end and at least one of the first
and second fenestrations is disposed in the proximal end of its
respective recessed region.
7. The stent graft of claim 6, wherein the first fenestration is
disposed in the proximal end of the first recessed region and the
second fenestration is disposed in the proximal end of the second
recessed region.
8. The stent graft of claim 1, wherein the first and second
recessed regions each comprise a diamond shape having first and
second proximal sides meeting at a proximal apex and first and
second distal sides meeting at a distal apex to form the diamond
shape of each recessed region, wherein a distal side of the first
recessed region shares the boundary with a proximal side of the
second recessed region.
9. The stent graft of claim 8, wherein the first stent is a first
zig zag stent and a second stent is a second zig zag stent directly
adjacent the first zig zag stent, wherein the first and second zig
zag stents define the diamond shape of the first recessed
region.
10. The stent graft of claim 9, further comprising a third zig zag
stent directly adjacent the second zig zag stent, wherein the
second and third zig zag stents define the diamond shape of the
second recessed region.
11. The stent graft of claim 10, wherein a single strut of the
second zig zag stent defines a distal side of the first diamond
shape and the proximal side of the second diamond shape.
12. The stent graft of claim 8, wherein proximally of the first
diamond shape the tubular body has a first diameter, distally of
the second diamond shape the tubular body has a second diameter,
and in an intermediate region of the tubular body around the
diamond shapes, the tubular body has a third diameter, the first
diameter being greater than the second diameter and both the first
and second diameter being greater than the third diameter.
13. The stent graft of claim 12, wherein the intermediate region
tapers on only one side of the stent graft and the first and second
recessed regions are disposed substantially in the taper of the
intermediate region.
14. The stent graft of claim 1, wherein the first fenestration is
proximal of the second fenestration.
15. A stent graft for placement in vessel of a patient, the stent
graft comprising; a tubular body of graft material, the tubular
body defining a main lumen therethrough, the graft material
defining a side wall, a plurality of zig zag stents along the
tubular body, each of the stents comprising a plurality of struts
and points or bends, each point or bend being disposed between a
pair of adjacent struts; a first shaped recess in the side wall of
the graft material of the tubular body having a perimeter, the
perimeter being formed at least in part by two adjacent struts of a
first stent of the plurality of zig zag stents and two adjacent
struts of a second adjacent stent of the plurality of zig zag
stents; a second shaped recess in the side wall of the graft
material of the tubular body having a perimeter, the perimeter
being formed at least in part by two adjacent struts of the second
stent of the plurality of zig zag stents and two adjacent struts of
a third adjacent stent of the plurality of zig zag stents, wherein
the first shaped recess and the second shaped recess share a
boundary at one of the two adjacent struts of the second stent and
are longitudinally and circumferentially offset from one another;
the shaped recesses being defined by a respective recessed portion
of the graft material that extends into the main lumen of the
tubular body, the shaped recesses, having a proximal end; a first
fenestration in the first recessed portion of graft material, the
first fenestration opening into the tubular body from the first
shaped recess; a second fenestration in the second recessed portion
of graft material, the second fenestration opening into the tubular
body from the second shaped recess a first graft tube leading from
the first fenestration into the main lumen and comprising a
reinforcing assembly in the form of a space frame; and a second
graft tube leading from the second fenestration into the main lumen
and comprising a reinforcing assembly in the form of a space
frame.
16. The stent graft of claim 15, wherein the first graft tube
extends from the proximal end of the first shaped recess and the
second graft tube extends from the proximal end of the second
shaped recess.
17. The stent graft of claim 16, wherein the stent graft comprises
a proximal end and a distal end and each of the first and second
graft tubes extend within the main lumen towards the proximal end
of the stent graft.
18. The stent graft of claim 15, wherein each space frame comprises
a cylindrical portion, each cylindrical portion comprising first
and second circular ring portions spaced apart axially and at least
two struts extending between the first and second circular ring
portions and each graft tube being around the space frame.
19. The stent graft of claim 15, wherein the first graft tube has a
greater diameter than the second graft tube.
20. The stent graft of claim 15, wherein each space frame comprises
a cylindrical portion, each cylindrical portion comprises an
assembly of two individual ring and strut components, each ring
comprising a circular ring portion defining a plane of the circular
ring portion and a strut extending at right angles to the plane of
the circular ring portion from a periphery of the circular ring
portion.
21. A stent graft for placement in a vessel of a patient, the stent
graft having a proximal end and a distal end, the stent graft
comprising: a tubular body of graft material, the tubular body
having a main lumen therethrough, the graft material defining an
side wall, a plurality of discrete zig zag stents along the tubular
body, each of the stents comprising a plurality of struts and
bends, with each bend being disposed between a pair of adjacent
struts; at least a first stent of the plurality of zig zag stents,
a second stent of the plurality of zig zag stents adjacent to the
first stent, and a third stent of the plurality of zig zag stents
adjacent to the second stent, the first stent having a pair of
adjacent bends substantially aligned with a pair of adjacent pair
of bends of the second stent and the second stent having a pair of
adjacent bends substantially aligned with a pair of adjacent pair
of bends of the third stent, whereby a pair of adjacent struts of
the first stent and a pair of adjacent struts of the second stent
together define a first diamond shaped region and a pair of
adjacent struts of the second stent and the third stent together
define a second diamond shaped region; a first recess in the first
diamond shaped region, the first recess being defined by a first
recessed portion of the side wall of the graft material that
extends into the main lumen of the tubular body, the first recess
having a proximal end; a second recess in the second diamond shaped
region longitudinally and circumferentially offset from the first
recess, the second recess being defined by a second recessed
portion of the side wall of the graft material that extends into
the main lumen of the tubular body, the second recess having a
proximal end; a first fenestration in the first recessed portion of
graft material, the first fenestration opening into the tubular
body from the first recess in the first diamond shaped region; a
second fenestration in the second recessed portion of graft
material, the second fenestration opening into the tubular body
from the second recess in the second diamond shaped region; a first
graft tube leading from the first fenestration into the main lumen,
the first fenestration and the first graft tube extending from the
proximal end of the first recess towards the proximal end of the
stent graft; and a second graft tube leading from the second
fenestration into the main lumen, the second fenestration and the
second graft tube extending from the proximal end of the second
recess towards the proximal end of the stent graft.
Description
BACKGROUND
1. Technical Field
This invention relates to a medical device for treatment of aortic
arch disease and more particularly to a stent graft for deployment
into the thoracic aorta of a patient for that purpose.
2. Background Information
In recent years endovascular implantable devices have been
developed for treatment of aortic aneurysms. These devices are
delivered to the treatment site through the vascular system of the
patient rather than by open surgery. The devices include a tubular
or cylindrical framework or scaffolding of one or more stents to
which is secured a tubular shape of graft material such as woven
Dacron, polyester polytetrafluoroethylene or the like. The devices
are initially reduced to a small diameter, placed into the leading
or proximal end of a catheter delivery system whereafter the
delivery system is inserted into the vascular system of the patient
such as through a femoral incision. The leading end of the delivery
system is maneuvered to the treatment site over a previously
positioned guide wire. Through manipulation of a control system
that extends to the proximal end of the catheter from the distal
end of the system outside the patient the implantable device is
then deployed by holding the device at its location and withdrawing
a surrounding sheath. The stent graft or implantable device can
then self expand or is expanded through the use of a balloon which
is introduced with the stent graft introduction device. The stent
graft becomes anchored into position to healthy wall tissue in the
aorta such as by barbs whereafter the delivery system is then
removed leaving the device in position to reverse an aneurysm in
the aorta in a manner that channels all blood flow through the
stent graft so that no blood flow enters the aneurysm thereafter,
such that not only does the aneurysm no longer continue to grow and
possibly rupture but the aneurysm actually begins to shrink and
commonly disappears entirely.
For treatment of thoracic aortic aneurysms in particular it is
necessary to introduce the implantable device high up in the aorta
and in a region of the aorta which is curved and where there can be
strong blood flow.
In the thoracic aorta there are major branch vessels, the
brachiocephalic, the left carotid and the left subclavian and for
treatment of an aneurysm in the region of the thoracic arch
provision must be made for blood supply to continue to these
arteries. For this purpose fenestrations are provided into the wall
of a stent graft in that region. Access is generally obtained to
these fenestrations, to deploy side arms into the stent graft, via
the left or right brachial arteries or less commonly via the left
or right carotid arteries. Once into the thoracic arch via such an
artery the fenestration in the stent graft must be
catheterised.
If a stent graft has been deployed into the thoracic aorta around
the arch such that its fenestrations are not aligned precisely with
their corresponding great vessels of the arch, then it can be
difficult to access the fenestrations through corresponding vessels
(such as the brachiocephalic and the left brachial arteries).
It is the object of this invention to provide an arrangement of
stent graft to overcome the above problem or to at least provide
the practitioner with a useful alternative.
Throughout this specification the term distal with respect to a
portion of the aorta, a deployment device or a prosthesis such as a
stent graft is intended to mean the end of the aorta, deployment
device or prosthesis such as a stent graft further away in the
direction of blood flow from the heart and the term proximal is
intended to mean the portion of the aorta, deployment device or end
of the prosthesis nearer to the heart. For other lumens within the
human or animal body the terms caudal and cranial respectively
should be understood.
Throughout this discussion the term "stent graft" is intended to
mean a device which has a tubular body of biocompatible graft
material and at least one stent fastened to the tubular body to
define a lumen through the stent graft. The stent graft may be
bifurcated and have fenestrations, side arms or the like. Other
arrangements of stent grafts are also within the scope of the
invention.
BRIEF SUMMARY
In one form therefore the invention is said to reside in a stent
graft for placement in the thoracic arch of a patient, the stent
graft comprising:
a tubular body defining a main lumen therethrough, a plurality of
zig zag stents along the tubular body, each of the stents
comprising a plurality of struts and bends, the bends being between
adjacent struts;
at least a first stent and an adjacent second stent, the first and
second stents having at least a pair of adjacent bends on the first
stent aligned with an adjacent pair of bends on the second stent,
whereby a first pair of adjacent struts of the first stent and a
second pair of adjacent struts of the second adjacent stent
together define a diamond shaped region;
a recess in the diamond shaped region, the recess being defined by
a concave portion of graft material and the recess extending into
the lumen of the tubular body, the recess having a proximal
end;
a fenestration in the concave portion of graft material, the
fenestration opening into the tubular body within the recess in the
diamond shaped region; and
a graft tube leading from the fenestration into the main lumen.
Preferably the fenestration and graft tube extend from the proximal
end of the recess.
In one form the stent graft further comprises:
a third adjacent stent, the third adjacent stent having at least a
pair of bends adjacent to the second stent whereby a third pair of
adjacent stents of the third strut defines a second diamond shaped
region,
wherein the second diamond shaped region shares a strut with the
first diamond shaped region.
Preferably the stent graft comprises one, two or three diamond
shaped regions, each diamond shaped region comprising a respective
recess, fenestration and graft tube.
Preferably the stent graft comprises a proximal end and a distal
end and the, or each, graft tube extends within the main lumen
towards the proximal end of the stent graft.
Preferably the bends and adjacent struts define an included angle
in the range of from 40 to 80 degrees.
Preferably proximally of the diamond shaped region the tubular body
has a first diameter, distally of the diamond shaped region the
tubular body has a second diameter and in a region of the tubular
body around the diamond shaped region the tubular body has a third
diameter, the first diameter being greater than the second diameter
and both the first and second diameter being greater than the third
diameter whereby a central region is defined which will allow at
least part circumferential blood flow during an operation out of
the graft tube into the recess and then into the central
region.
It will be seen that by this invention there is provided a stent
graft for placement in the thoracic arch of a patient. The stent
graft can be placed such that the intermediate portion is just
proximal of the brachiocephalic artery and on the outside of the
curve of the thoracic arch. By this placement there is defined, by
the difference in diameter of the first and second portions, an
open region outside the stent graft distal of the aperture in the
step portion, so that blood flow can occur through the aperture to
the open region enabling circulation to be preserved to the major
vessels through the internal branches during the progress of an
operation. As the intermediate portion is of stent graft is of a
lesser diameter there is provided a working space in the recess in
which a guide wire from the branch arteries can be directed to
enter the internal tube to enable catheterisation. Subsequently a
side branch stent graft can be deployed from the respective branch
artery into the tube to provide blood flow into that branch
artery.
In a preferred embodiment the first diameter can be from 35 to 50
mm, the second diameter can be from 40 to 30 mm, the third diameter
can be from 20 to 40 mm. For instance in one embodiment the first
diameter is 46 mm and the second and third diameters are 38 mm. In
another embodiment the first and third diameters are 36 mm and the
third diameter is 24 mm.
In one form the stents are formed from nitinol.
In one form the or each graft tube comprises a reinforcement in the
form of a space frame.
In one form the space frame comprises a cylindrical portion the
cylindrical portion comprising first and second circular ring
portions spaced apart axially and at least two struts extending
between the first and second circular ring portions and the graft
tube being around the space frame.
In one form the cylindrical portion comprises an assembly of two
individual ring and strut components, each ring and strut component
comprising a circular ring portion defining a plane of the circular
ring portion and a strut extending at right angles to the plane of
the circular ring portion from a periphery of the circular ring
portion.
In an alternative form the invention is said to reside in a stent
graft for placement in the thoracic arch of a patient, the stent
graft comprising:
a tubular body defining a main lumen therethrough, a plurality of
zig zag stents along the tubular body, each of the stents
comprising a plurality of struts and points or bends, the points or
bends being between adjacent struts;
a shaped recess in the tubular body having a perimeter, the
perimeter being formed at least in part at two adjacent struts of a
first stent and two adjacent struts of a second adjacent stent;
the shaped recess being defined by a concave portion of graft
material and the shaped recess extending into the lumen of the
tubular body, the shaped recess having a proximal end;
a fenestration in the concave portion of graft material, the
fenestration opening into the tubular body within the shaped
recess; and
a graft tube leading from the fenestration into the main lumen.
Preferably the fenestration and graft tube extend from the proximal
end of the shaped recess.
In one form the stent graft further comprises:
a second shaped recess in the tubular body defined by a second
perimeter, the second perimeter being formed at least in part at
two adjacent struts of the second stent and two adjacent struts of
a third adjacent stent.
In one form the stent graft further comprises: a proximal end and a
distal end and the or each graft tube extends within the main lumen
towards the proximal end of the stent graft.
Preferably the bends and adjacent struts define an included angle
in the range of from 40 to 80 degrees.
In one form the stents are formed from nitinol.
In one form the or each graft tube comprises a reinforcement in the
form of a space frame.
In one form the space frame comprises a cylindrical portion the
cylindrical portion comprising first and second circular ring
portions spaced apart axially and at least two struts extending
between the first and second circular ring portions and the graft
tube being around the space frame.
In one form the cylindrical portion comprises an assembly of two
individual ring and strut components, each ring and strut component
comprising a circular ring portion defining a plane of the circular
ring portion and a strut extending at right angles to the plane of
the circular ring portion from a periphery of the circular ring
portion.
In a further alternative form the invention is said to reside in a
stent graft for placement in the thoracic arch of a patient, the
stent graft comprising:
a tubular body defining a main lumen therethrough, a plurality of
zig zag stents along the tubular body, each of the stents
comprising a plurality of struts and bends, the bends being between
adjacent struts;
at least a first stent and an adjacent second stent, the first and
second stents having at least a pair of adjacent bends on the first
stent aligned with an adjacent pair of bends on the second stent,
whereby a first pair of adjacent struts of the first stent and a
second pair of adjacent struts of the second adjacent stent
together define a diamond shaped region;
a recess in the diamond shaped region, the recess being defined by
a concave portion of graft material and the recess extending into
the lumen of the tubular body, the recess having a proximal
end;
a fenestration in the concave portion of graft material, the
fenestration opening into the tubular body within the recess in the
diamond shaped region; and
a graft tube leading from the fenestration into the main lumen, the
fenestration and graft tube extending from the proximal end of the
recess towards the proximal end of the stent graft.
BRIEF DESCRIPTION OF THE DRAWINGS
This then generally describes the invention but to assist with
understanding reference will now be made to the accompanying
drawings which show preferred embodiments of the invention.
In the drawings:
FIG. 1 shows a plain view of a first embodiment of a stent graft
according to the present invention;
FIG. 2 shows a side view of the stent graft of FIG. 1;
FIG. 3 is an isometric view looking in a slightly distal direction
along the stent graft of FIG. 2;
FIG. 4 shows a view from the proximal end of the stent graft shown
in FIG. 1;
FIG. 5 shows a longitudinal cross-sectional view of the stent graft
shown in FIG. 1;
FIG. 6 shows a schematic view of the placement of a stent graft
according to the present invention into the thoracic arch of a
patient; and
FIG. 7 shows a plan view of a second embodiment of a stent graft
according to the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED
EMBODIMENTS
FIGS. 1 to 6 show an embodiment of stent graft according to the
present invention. In this embodiment the tubular body 52 of this
embodiment of stent graft 50 comprises a proximal portion 54, an
intermediate portion 56 and a distal portion 58 as shown in FIG.
5.
Referring to FIG. 1 it can be seen that the proximal portion 54
comprises a tubular body of a biocompatible graft material and is
supported by self expanding zig zag stents 60a and 60b. The stent
60a is internal to provide a smooth sealing surface to engage
against the wall of the ascending aorta, and the stent 60b is
external. The proximal portion may have a diameter from 35 to 50
mm.
The distal portion 58 is again formed from a tubular body of a
biocompatible graft material and is supported by self expanding zig
zag stents 82 and 84. The distal portion 58 can have a diameter in
the range of from 30 to 40 mm.
The intermediate portion 56 is supported by self expanding zig zag
stents 64 and 66 and is the region into which are placed the
diamond shaped regions and the recess according to the present
invention. The intermediate portion has a diameter in the range
from 20 to 30 mm and had tapered portions at each end to connect
with the proximal and distal portions respectively.
The stents 64, 66 and 68 comprise a plurality of struts and bends,
the bends between the adjacent struts. In the embodiment shown, the
struts are substantially longer than the bends, the bends having a
relatively small radius. The stents are made from shape memory wire
in the form of nitinol (metal alloy of nickel and titanium).
The intermediate portion 56 has a diameter at its proximal end 61
which is substantially the same as the diameter of the proximal
portion 54 and a diameter at its distal end which is substantially
the same as the diameter of the distal portion 58. The intermediate
portion 56 has most, if not all of its taper between the diameter
of the proximal portion and the diameter of the distal portion on
the outside 72 of the curve of the stent graft.
As can be seen in FIG. 1 the intermediate portion 56 has two
apertures or fenestrations 74 and 75 which open into respective
recesses 76 and 77 within the step portion and graft tubes from the
recesses extends proximally towards the proximal portion 54.
Adjacent stents 64 and 66 are positioned such that they define a
diamond shape region 76a. The diamond shape arises from having a
pair of distal bends 64b and 64d of stent 64 aligned with a pair of
proximal bends 66b and 66d of stent 66 as is clearly shown in FIG.
1. A first pair of adjacent struts 64b' and 64c' of stent 64 and a
second pair of adjacent struts 66b' and 66c' of the adjacent stent
66 together define a diamond shaped region 76a.
A recess 76 lies within the diamond shape region 76a. A
fenestration 74 into the tubular body leads from recess 76 into a
graft tube 78. The graft tube 78 extends within the tubular body
towards a proximal end of the stent graft as is most clearly shown
in the cross-sectional view of FIG. 5.
A third adjacent stent 68 has a pair of bends 68a and 68c adjacent
to the second stent 66 such that a third pair of adjacent stents
68a' and 68b' define a second diamond shape region 77a. The second
diamond shape region 77a shares a strut 66b' with the first diamond
shape region 76a.
In this particular embodiment stent 64 has fourteen bends (seven
distal bends and seven proximal bends) and stent 66 has twelve
bends (six distal bends and six proximal bends). As a result of the
differing number of bends and the alignment described above, distal
bends of stent 64 are not aligned with proximal bends of stent 66
at the inside radius of the stent graft, the side of the stent
graft without the diamond shaped regions, when it is placed in the
arch as illustrated in FIG. 6. This assists in providing
flexibility so as to facilitate the stent graft conforming to the
anatomy of the thoracic arch as is shown in FIG. 6. In other
embodiments different numbers of struts and bends may be used. In
general, however, it is preferable for adjacent stents to have
different numbers of struts and bends so that on the side of the
stent graft without the fenestrations and recesses the bends do not
coincide thereby allowing better flexibility.
The diamond shape regions and recesses 76a and 77a facilitate
insertion of guide wires from the major branch arteries (such as
the brachiocephalic and the left carotid artery) into the internal
tubes 78 and 80 of the stent graft 50.
With the embodiment shown in FIGS. 1 to 6, the diamond shape
regions 76a and 77a are adjacent each other and are separated by a
strut 66b' of stent 66. With this arrangement, the corresponding
fenestrations 74 and 75 are offset from each other so that one is
slightly more ventral than the other with respect to the thoracic
arch.
The recess 76 within the intermediate portion 56 opens at its
proximal end into a tube 78 and the recess 77 opens at its proximal
end into a tube 80. Each of the tubes may be of the same diameter
or the uppermost of the tubes 78 may have a diameter which is
greater than the diameter of the lower tube 80. The tubes 78 and 80
extend towards the proximal end 61 of the stent graft 50.
The proximal end of the tubes 78 and 80 are held open by
reinforcing wires, or wire portions, 78a and 80a respectively,
these wires arranged to form circles as is shown in the
cross-sectional view of FIG. 5.
The tubes 78 and 80 also have reinforcing wires, or wire portions,
78b and 80b arranged to hold the respective distal ends of the
tubes open as is more clearly shown in FIG. 3.
Extending from reinforcing wire 78a, past reinforcing wire 78b and
to bend 66c is a longitudinal reinforcing wire, or wire portion 78c
as is most clearly shown in FIG. 1. Similarly, extending from
reinforcing wire 78a, past reinforcing wire 80a and to bend 68b is
a longitudinal reinforcing wire, or wire portion 80c.
Each of the smaller internal tubes 78 and 80 can be reinforced with
a helical shape memory wire reinforcement. Helical reinforcement
for graft material is shown in U.S. patent application Ser. No.
12/261,860 entitled "Flexible Stent Graft" and the teachings
therein are incorporated herein in their entirety.
FIG. 6 shows a schematic view of the placement of a stent graft
according to one embodiment of the present invention into the
thoracic arch of a patient.
The thoracic arch shown schematically comprises an ascending aorta
90 extending to the thoracic arch 92 and a descending aorta 94 from
the thoracic arch. Substantially at the top of the thoracic arch
but slightly to the ventral side of the arch the major vessels
branch off the arch. The major vessels are the brachiocephalic
artery 96, the left common carotid artery 98 and the left
subclavian 100. In a preparatory operation an anastomosis 102 is
provided between the common carotid artery 98 and the left
subclavian 100. The anastomosis provides access between the common
carotid artery 98 and the left subclavian artery 100 which enables
endovascular access to the stent graft via brachial arteries in the
left arm rather than endovascular access via the left carotid
artery which may be more complex.
The stent graft 50 is deployed into the thoracic arch such that the
intermediate portion 56 is just proximal of the junction of the
aorta with the brachiocephalic artery 96. This means that there is
defined between the intermediate portion 56, the upper wall of the
thoracic arch and the distal portion 58 of the stent graft 50, an
open region 111 so that circulation can be preserved to the major
vessels through the internal tubes 78 and 80 and the recess 76 (see
FIGS. 3 and 4) during the operation of deployment of the stent
graft and subsequent placement of side branch grafts. The space
also assists in enabling catheterisation of the internal tubes. A
catheter 110 can be inserted to enter the larger of the tubes 78 to
enable placement of a side branch stent graft 114 for the
brachiocephalic artery 96 and a catheter 112 can be inserted to
enter the smaller of the tubes 80 to enable placement of a side
branch stent graft 116 for the common carotid artery 98 and the
left subclavian artery 100. Subsequently a side branch stent graft
can be deployed from the respective branch artery into one of the
smaller tubes to provide blood flow into that branch artery.
Because the space 111 provides maintenance of circulation to the
major vessels there may be circumstances where an operation can be
carried out in stages.
In a preferred embodiment the larger of the internal tubes 78 has a
diameter of from 8 to 12 mm and the smaller of the tubes has a
diameter of from 8 to 10 mm.
The graft tubes extending into the main lumen can have a
reinforcement in the form of a space frame. The components of the
space frame can be an assembly of two ring and strut components.
Each ring and strut component comprises a circular ring portion
defining a plane of the circular ring portion and a strut extending
at right angles to the plane of the circular ring portion from a
periphery of the circular ring portion. Each of the two ring and
strut components are formed from a single length of a rigid but
resilient wire such as a nickel titanium alloy wire. At each end of
each piece of wire a loop is formed to ensure that a sharp end
which could puncture a vessel wall is not present. Once the
components of the lightweight space frame are formed they have
stitched to them portions of biocompatible graft material to form
separately the tubular portion and the funnel portion and then
these are joined together by stitching or the like.
FIG. 7 shows an alternative embodiment. This embodiment is similar
to that shown in FIGS. 1 to 6 but it includes a third diamond
shaped region 47a with its corresponding recess 47 and fenestration
45. In other embodiments, not shown, there can be a single diamond
shaped region, multiple diamond shaped regions aligned
longitudinally or other layouts of the regions.
Many modifications and other embodiments of the invention will come
to the mind of one skilled in the art having the benefit of the
teachings presented in the foregoing descriptions and associated
drawings. Therefore, it is understood that the invention is not to
be limited to the specific embodiments disclosed, and that
modifications and embodiments are intended to be included within
the scope of the appended claims.
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